Apparatus for holding glass.



Patented AUQ. 29, I899.

a. A. MARSH. APPARATUS FOR HOLDING GLASS.

[Application filed Feb. 7, meal 2 Sheets$heet (No Model.)

N0. 63|,855. Patented Aug. 29 I899- a. A. MARSH.

' APPARATUS FOR HGLDlNG GLASS.

[Application filed Feb. 7, 1898.1 v (N MGdeI.) 2 Sheets8heet 2 W/i fi z?5. 1 3' 175%)/ q 1/21/2342 I NVE NTOR a. W MW enonennr'iinasn, orPlT-TSBURG, PENNSYLVANIA; ASSI'GNOR To ran? anse PLATE GLASS (murmur, onSAME PL' oE.

'APPARTUS son serum 4 games.

.srncirrcnigzonfi ia m of Letters Paar No. earssoaoma August 29, I899.

' Applieation filed'feliruary 7, 1898. Serial N:, 669g437:: No modeL':

Toia ZZ whom it may concern.-

Be'itk'n'own that I, GEORGE A. M-Aesu, oi Rittsburg, in the. county oiAllegheny State QfiPenns ylw ania-fihawt n; n d 511 mo eme i Holding ofwhich the following-is gran:

clear, andex actdescription, i eferencebeing ,1 p I andlfith'corresponding outlet-port, the outliad the accompanying drawings; .pairtot thisfrlspeeific'atio'n;infwhich---v i0 Figure 1 is a top plan'view, partlybroken 7 away', of a table constructed in accordance with my inventionwith the flat packing 'in plahethereon. Fig.-2-is a bottom plan View ofthe tab e. Figs. 3 and 4 are enlarged sectional views, taken atrightangles' to each other of one of, the sections. ',Fig. 5 is anenlarged detail View showingthe juncture of two sheets over,awater-channeliandjiig. 6

. i's 'a' detail View. of the release-Valvel eifiploy, 7 My inventionrelates to that class'of tables for holding plate-glass wherein a vacuumsys-' 'tem is employed; and it consists in an'im proved construction ofthe table and'its chambers-and-snpportiug-ribs forthe glass, in arelief-valve to prevent the vacuum from ex? eeeding' a' predetermined.limit, .in means for heating 'the edge portions of .the table, and

generally in the construction and arrange;

.ment ofthe parts, as hereinafter more fully described, and set forth inthe claims.

v Irwill first describe that part of my inven- V tion'tjvhich'relates tothesystein-of chambers inthe -table,; the invent'ion in this respectrelating'totliat system of chambers-described in myPatent No. 477,305,dated June 22, v l 892. In the said patent I show above'thevacuum-chambers of the table a chamber arranged to contain a heating foicooliugn'nedium, such as water. tion I place the vacuum-chambers and thefluidchainbersfside by side in substantially the same plane. "Thus inthe table 2, (shown in the drawings) which is preferably com posed ofsix sections 3, I provide each section with vaouum-chambers4, whichextend alternately from each-end of, each'se ction to a pointnear-theother end, as shown by dotted lines in Fig. 3. Each of thesevacuum-chambers communicates with a chamber 5, cast upon the bottom ofeach section, the chainbers '5 being connected by branch pipes G tableand the-glass being placed upon this In my new constru'c-' v let beinglocated at the diagonally opposite 6o corner of the section from theinlet, so that the water is compelled to traverse and heat or cool theentiresection before it passes out,

In Fig. 2 I show the fluid-pipe system, 11 bein'gtlie supplypipe,havingbranches entering the end sections ofithe table at the points 9.' Thewater havingtraversed each section,

passing in the circuitous course through the water chauibers, passes outthrough the diagonally opposite' corner into connecting-pipes 1 2, whichlead to the supply-ports of-th'e ad jacent sections, The two separatecurrents of water thus continue longitudinally ofthe table and are takenoft through outle -pipes :13. The several pipes are s cured in place,af-ter thesections-ar'e cast, an the system is especially adapted l'orease, simplicity; and

cheapness of construction.

Each sectio'nof the table is divided into a numberof cells by means ofthe parallel ribs 14, which form surface-channels, into which the waterpasses through the small holes 15, connecting with the water-chambers.Eacheel-his connected by a suitable hole 16 with oneof theyauum-cham'bers, and the opera- 85.-

tion of the table is similar to that described in myabove-recitedpatent,-a packing of paperor similar material-17 beingilaidover'the 2senses many other forms may be easily devised, the essential point beingthat they shall be evenly and uniformly distributed within the cell. Itis also necessary in order to give perfect support for the glass 'thatthe area of the bearing-surface of theseribs should be equal 'to andpreferably greater than the area of the vacuum-space between them.Thus-if the area of aicell is, say, forty-nine inches I preferablyprovide about twenty-nine square inches of bearingsurface, leaving abouttwenty square inchesof vacuum-surface. Itis characteristic ofpolishing-machines that the operative area of the polishing-disksisconsiderablyless than the area of the supporting-table and the sheetsof glass secured thereon and that in order to bring all portions of thesurface of the glass uniformly under the action of the polishingdisksthe frame carrying the latter is reciprocated'back and-forth, and theglass-supportin g table is also reciprocated back and forth, but in adirection at right angles to the line of movement of thepolishing-disks. It follows from these characteristics that while themiddle' portions of a sheet of glass will be subjected to the nearlyconstant action of the disks the portions of the sheet adjacent to theedges will be shifted in and out from in under thepolishing-disks andwill therefore be sub;

.jected to a considerable loss of heat by radiation. To compensate forthis loss of heat and to maintain all portions-of the sheet at or nearlyat the same temperature, I provide means whereby heat can be appliedlocally to the edges of the table, such 'means being independent of.-anymeans employed for'regulating the'temperaturerof the middle portions ofthe table. A convenient means for efiecting this purpose consists of apipe 19,, o, seouredto the edges of the table and connected to asteam-supply. This pipe may consist of a series of independent sectionsconnected by .short pipe-sections 20. The

gmiddle portions of the glass-sheet being con-.

' edge portions will not be subjected as constantly and uniformly to theaction of the disks and will be-subjected to loss by radiation. Byapplying a highly-heated fluid to the edges of the table'the portions ofglass adjacent thereto can be raised and maintained at or nearlyat thesame temperature as the portions constantly under the polishing-disks.

A very important part of'my invention consists in a relief-valve 21,which is arranged to prevent the pressure on the glass fromexoeeding apredetermined limit. I show one formof this valve in Fig. 6, thevalve-casing 22 having within it the upwardly-movable valve 23, to whichis hungaweigh-t 24. This valve is connected to the main vacuum-pipetermined by the size of the \veiglit- -tlicx'alvc ceeding a certaindetermined amount, the action being the reverse of a safety-valve upon apressure system. valve, as well as the pointat which it is at-. tached,may be varied wldely without depart-' ing from this part of-myinvention, since I consider myself the first to use a relief-valve upona vacuumtable for holding glass.

In order to prevent water seeping up between the edges of. the matchedplates where channels,I place over the paper at this-point a strip ofnon-porous material 25, asshown in The form of this relief" theirjuncture comes over one of the Water- Fig. 5, since unless this wereused the water would creep onto the upper faces of the glass plates andinterfere with the grinding or polishing.

The advantages of the various parts of my invention will be apparent tothose skilled in this art. The alternate arrangement of thevacuum-chambers and the liquid chambers gives a simple form ofconstruction, while the conductivity of .the iron or metal composing thesections insures a practically uniform distribution of the heating orcooling action of the liquid. The liquid is uniformly distributed, sothat there will be no excess at any point in the water-channels, and thearrangement of the chambers is such that the liquid traverses all partsof each section before passing to the next. The check-valve is anessentialifeature, as it prevents the possibility of too great apressure being brought upon the glass." The pipe surrounding the tableand arranged to contain a heating fluid enables the outer parts of thetable to be kept at a uniform temperature with the inner por tions, andthe non-porous strip at the meet ing edges of the plates,'where suchedges are above the water-channel, prevents access of water tothe upperface of the plates.

Many changes in the form, construction, an (1' relative arrangement ofthe parts may be made by those skilled-in the art without variance frommy invention, since What I claim'is 1. A table for holding glassprovided with a series of fluid-chambers and a series of vacuum-chambersarranged intermediate of "and connecting-passages between the oppositeends of the liquid-chambers.

3. A vacuum-table for holding glass, having vacuum-chambers thereinextending alternately from each end to a point near the other end,'andliquid-ohambers between the vacuum-chambers, said liquid-chambersconnecting with each other at their ends. at a, suitable point, and itis evident that when the vacuum-passesa certain limit de;

4, A vacuunl-table for holding glass, having vacuum-chambers therein.said table having a series of open water-channels, and liquid-chamberswithin the table between the vacuum-chambers and communicating with saidWater-channels.

5. A vacuum-table for holding glass, havin g therein aseries ofvacuum-chambers, said table having open Water-channels on its upperface, and being provided between the vacuum chambers with connectedliquidchambers in communication with the Waterchannels.

6. A vacuum-table for holding glass, having therein a series ofvacuum-chambers extending alternately from each end to a point near theother end, said table having a series of open Water-channels on itsupper face, and being provided with liquid-chambers between thevacuum-chambers, said liquid-chambers being connected with each otherand communicating with the open channels.

'7. A vacuum-table for holding glass formed of several sections, eachsection having vacuuin-chambers and open liquid-channels communicatingwith liquid-chambers located between the vacuum-chambers, a liquid-mainhaving branches extending to the sections and connected to theliquid-chambers, and outlets from the liquid-chambers at the. oppositecorners of the sections.

8. In a vacuum-table for holding glass, a vacuum-cell having a sealingmeans surrounding the same, and a series of rib-supports distributedwithin the cell. the amount of bearing-surface of said supports being atleast substantially as great as the amount of vacuum-surface.

9. In a vacuum-table for holding glass, a

vacuum cell having a water-channel surrounding the same, and Within theWaterchannel a series of.uniforinly-distribnted supports, thebearing-surface of said supports being greater than the amount ofvacuumsurface Within the cell.

10. The combination of a glass-holding table, and heating means locatedadjacent to the edges of the table and arranged to so apply heat to theportions of the table adjacent to the edges as to maintain such portionsat approximately the same temperature as the body portion during thegrinding and polishing operation, substantially as set forth.

11. A glass-holding table having secured around the edges thereof aconduit for the passage of fluid for maintaining the portions of theglass adjacent to the edge portions of the table at approximately thesame temperature as the body or interior portions thereof, substantiallyas set forth.

12. In a vacuum-table for holding glass, a vacuum-cell having asurrounding open liquid-channel, and a strip of non-porous materialplaced above the channel and beneath the meeting edges of glass sheetsthereover.

13. In a vacuum-table for holding glass, the combination with avacuum-cell having a surrounding open liquid-channel, of porous packingfor the channel, and anon-porous strip upon the packing above thechannel.

In testimony whereof I have hereunto set my hand.

GEORGE A. MARSH.

Witnesses:

G. I. HOLDSHIP, G. E. MACKOWN.

